Switching matrice crosspoint

ABSTRACT

A miniature crosspoint having magnetic latching pairs of contacts is disclosed. Each pair of contacts includes a remanent magnetic conductor serving as a rigid core and a non-remanent magnetic conductive reed. The remanent magnetic conductors are paired with a pole piece to form an inverted U-shaped arrangement. Series fluxes are generated in the cores, and looped through the cores and the pole piece, in contacts not forming a pathway through the crosspoint switch, whereas parallel fluxes are generated in the cores and looped instead through the reeds which are attracted to contact the cores in a selected crosspoint.

United States Patent [1 1 Regnier et a1.

[451 Aug. 14, 1973 SWITCHING MATRICE CROSSPOINT [73 I Assignee: International Standard Electric Corporation, New York, N.Y.

[22] Filed: Nov. 26, 1971 [21] Appl. No.: 202,468

1,540,981 10/1968 France 335/152 Primary Examiner- Harold Broome Attorney C. Cornell Lombardi, Jr. et a1.

[ ABSTRACT A miniature crosspoint having magnetic latching pairs of contacts is disclosed. Each pair of contacts includes a remanent magnetic conductor serving as a rigid core and a non-remanent magnetic conductive reed. The remanent magnetic conductors are paired with a pole piece to fonn an inverted U-shaped arrangement. Series fluxes are generated in the cores, and looped through the cores and the pole piece, in contacts not forming a pathway through the crosspoint switch, whereas parallel fluxes are generated in the cores and looped instead through the reeds which are attracted to contact the cores in a selected crosspoint.

12 Claims, 4 Drawing Figures Remsen, Jr., Menotti J.

Patented Aug. 14, 1973 2 Sheds-Sheet 1 Patented Aug. 14, 1%73 2 Silesia-Sheet 2 1. SWITCHING MATRICE CROSSPOINT The present invention relates to magnetic latching sealedcontact crosspoints designed to be arranged in switching matrices and, particularly, coordinate control switching matrices.

Such crosspoints and matrices are well known with an'exam'ple thereof being described in an article enti-' tled Un autocommutateur te'le'phonique lectronique by Mr. A..l.Henquet issued in the No. 208 of the review Me'canique et Electricite'" of March, 1967.

Generally, such matricespermit a-plurality of circuits of the type A" to be connected to a plurality of circuits of the type Bvia crosspoints, each crosspoint defining a particular path between'a circuit A and a circuitB: Usually, the above mentionedmatrices are used for concentration or expansionpurposes, and usually the circuits A are more numerous or less numer'ousthan the circuitsB; One'circuit may be connected-to aplurality of other circuits via as many crosspoints as needed. In suchas case, when a commoncircuitis connected to a plurality of individual circuits,multiple linksconnectthe concerned terminals of the common circuit to the corresponding terminals of each crosspoint connected to an individual circuit via other terminals.

Practically, and particularly in the telephone switching field, the links betweenthecircuit terminals and the crosspoint terminals are usually embodied by connection wires soldered withtin alloy. It is well known that such solders are delicate'to make because of the small size ofmatrices, of the number of connection wires to be solderedand-of multiple wires-to be soldered, and that the soldering quality depends on'th'e'manner'of execution.

lf consideration'isgiven, for'example, to the needed links for connecting four circuits C, D, E and F to a fifth circuit G=by means of single contact crosspoints,

not less than 13 solderings'are' needed'for' making thelinks. Among those 13' solde'rings, there are, at least, three needed for'the multiples between outputs ofthe four used crosspoints.

- It appears to be of interest to reduce those solderings due to the multiples, as far as possible, because soldering reliability is lower than the reliability of a mean quality component.

The assembly reliability is then reduced in proportion with the increase of the soldering number, which is an important argument for reducing such a number, particularly for telephone switching matrices where any reduction of this-kind'at the level of the crosspoint corresponds to a very important increase in assembly reliability.

It is also known that the volume of telephone ex changes is still very'importantdue to thenumber of the subscribers and the rangeofthe-required'services, andis therefore of interestto reduce the size of the components and, particularly, of the matrix crosspoints' and, consequently, of the matrices.

An object of the present invention is therefore to provide a cross-pointcorresponding to those two goals, i.e. making it possible to reduce matrice size and to reduce the number of soldered connections.

I 'Therefore, according to the present invention, there is provided a crosspoint providing the independent connection of a pair of terminals to at leastone other pair of terminals, and having contacts and multiples relative to these contacts located inside a single tight capsule, corresponding to that crosspoint.

According to'- a feature of the invention, the crosspoint, controlled by current pulses, with magnetic latching, comprises 2m mobile contacts'located'in a single capsule and divided into m pairs of contacts, wherein each contact includes a rigid core element made of magnetic and electric conductive material and having'at'least a portion thereof composed of remanent magnetic material, and furtherincludes a flexible reed element made of non-remanent magnetic, electric conductive materialarranged to be'movable for contacting the associated core, and wherein each ofsaid m contact pairs provides for one of its reeds to be arranged with one of the" reeds of each of the other contact pairs in a-first integral'struct'ure and the other of its reeds to be arranged with the other of the reeds of each of the other contact pairs in a second integral structure, and further comprising a rod-like rigid carrier element made of'electric'conductive material associated with each of said first and second integral structures of reeds, said'rods and said 2m cores being sealed in the base of the capsule so asto form projections outside the capsule.

2m'control coils are mounted on the 2m cores. Each coilcomprises two identical windings around the core projection outside the capsule.

The connections are effected by means of printed circuit wires on a carrier boardcoupled to the cores and rods the board being arranged to be between the glass capsule and the control coils. The printed wires are'located on the other side of the board with respect to the glass capsule and are individually soldered to a core, a rod, or a winding terminal, depending on the desired configuration.

The magnetic shield is formed by a pole piece of nonremanent magnetic material, arranged about the core projections on the other side of the windings with respect to the glass capsule and the carrier board without electric contact between the shield and the cores occurring.

According to a feature of the invention, each core has a contact area permitting the reed with which it forms a contact to prop on it, and the 2m prop areas of the 2m cores are in the same plane, called the prop plane.

According to another feature of the invention, the 2m working faces of the 2m reeds are in a plane parallel to the prop plane, when the reeds are at rest, the distance between the reed working face plane and the prop plane being equal to the contact magnetic gap.

According to another feature of the invention, the two contacts of a pair of contacts are in the same condition at the same time, i.e. at rest when the remanent magnetizationsof their respective cores are in series, and operative when the remanent magnetizations of their cores are in parallel, the crosspoint being coordinate controlled.

According to another feature of the invention, the number m of pairs of contacts is equal to four.

According to another feature of the invention, the four reeds carried by a rod are arranged two and two located in two as opposite quadrants of the plane that they define, parallel to the prop plane so that the two reeds which form with two cores a pair of contacts such as hereabove defined, are connected one to the first rod and theother one to the other rod.

According to another feature of the invention, each core comprises two linear ends, one of which is free and constituting the prop area, and is parallel to the prop plane, and the other one is perpendicular to the prop plane and sealed in the glass capsule base.

According to another feature of the invention, each reed has its axis normal to the core plane so that each reed has the same relative position with respect to the core with which it forms a contact, as any other reed with respect to its respective core.

According to another feature of the invention, the four reeds carried by the same rod are made of material different of the rod material and are electrically welded to the rod so as to form a single piece.

Other features of the invention will appear from the following description of embodiments, the description being made in conjunction with the accompanying drawings, wherein:

FIG. 1 shows a pair of contacts of a crosspoint according to the invention and the electric links thereof with a pair of contacts of another crosspoint;

FIG. 2 shows the electric link and contact circuit of a crosspoint according to the invention, with respect to thepart located inside the capsule;

FIG. 3 shows an embodiment of a crosspoint according to circuit of the FIG. 2, from which four reeds, forming an intergral structure with a rod, have been removed in order to render the drawing easier to understand; and

FIG. 4 shows a topside view of the crosspoint shown in FIG. 3.

Referring to the FIG. 1, there is a pair 1 of crosspoint contacts arranged according to the invention. The pair 1 comprises two identical cores 2 and 3 of remanent magnetic conductor material, with the cores passing through respective holes 5 provided in a pole piece 4 of non-remanent magnetic material. The diameter of the said holes, as the hole 5 for the core 2 and the hole 6 for the core 3, is larger than the diameter of the core so that there is no contact between the pole piece 4 and the cores 2 and 3.

The cores 2 and 3 are not in contact and they are shaped so that the reluctance of the magnetic circuit formed by the pole piece 4 and the cores 2 and 3 is minimum. For this purpose, the cores 2 and 3 are L- shaped and are arranged so as to form together a reverse U.

Four identical coils 7, 8, 9 and 10 are two and two mounted around the cores 2 and 3, the coils 7 and 8 for magnetizing the core 2 and the coils 9 and 10 for magnetizing the core 3.

The coils are located on the same side of the pole piece 4 as the linear parts 11 and 12 of the L-shaped cores 2 and 3, those parts 11 and 12 being the parts not passing'through the holes of the pole piece 4. The cores 2 and 3 are sealed in the base of a glass capsule, not shown, such a base being located between the linear parts 11 and I2 and the tops of the coils 8 and 10.

The linear parts 11 and 12 are respectively located under the ends of the reeds 13 and 14 of flexible material which is conductive and non remanent magnetic so that the reed 13 may contact the linear part 11 of the core 2, and the reed 14 may contact the linear part 12 of the core 3 under magnetic action as it will be explained hereafter.

The reeds I3 and 14 are respectively carried by two rods [5 and 16 in conductor material and which are sealed in the glass capsule base so as to have their free ends projecting outside of the capsule. The capsule contains the linear parts 11 and 12 of the cores, the contact reeds l3 and 14, part of the cores 2 and 3 and part of the rods 15 and 16.

The ends of the cores 2 and 3 and of the rods 15 and 16 are each connected to an electric conductor wire such as 17 for the core 2, 18 for the core 3, 19 for the rod 15 and 20 for the rod 16.

The operation of the pair of contacts of the crosspoint 1, assembled in a matrix with other identical crosspoints as 21, may be controlled by coordinates according to the method described in the article mentioned hereinbefore. The pair of contacts 1 will thus have its operation controlled in a known manner by four pulses of predetermined intensity and duration. The first pulse is sent on the control wire of the vertical V0. The second pulse is of the same duration and is simultaneously sent on the control wire 23 of the horizontal Ho which is connected to the coil 10 and to all the coils having an identical position on each crosspoint of the horizontal Ho such as the coil 29 of the crosspoint 21. Likewise, the control wire 22 of the vertical V0 is connected to the coil 7 and to all the coils identically mounted in' the crosspoints of the vertical V0. The two other pulses are shorter than the first and the second ones and are sent simultaneously with the longer pulses. The third one is sent on the control wire 30 of the horizontal H'o connected to the coil 8 and to the coil 31 of the crosspoint 21 as well as to all the identically mounted coils of the horizontal Ho. The fourth one is sent on the control wire 32 of the vertical We to the coil 9 and to all identically mounted coils of the crosspoints of the vertical V'o.

In a known manner, after the pulses have disappeared, the magnetizations in the cores 2 and 3 are in parallel while, for the cores of the crosspoint 21, they are in series as well as for any other crosspoint of the same horizontal or the same vertical line as those of the crosspoint I.

For any crosspoint having the magnetizations of its cores in series, magnetic fluxes are closed through the cores and the pole piece thereof. As a result, such magnetizations have no effect on the flexible reeds.

For the crosspoint 1, the core magnetizations are parallel and the flux generated by each core can only be closed through the reeds and not through the other core; thus each reed is attracted by the corresponding core, as the reed 13 is attracted by the linear part 11 of the core 2 and the reed 14 by the linear part 12 of the core 3, a contact being so provided between each reed and the corresponding core.

As a matter of fact, it is known that the fluxes seek to reduce the length of their paths through which they are established for reducing the reluctance of the magnetic circuit. I

Data received on the wires 17v and 1.8, respectively connected to the cbres 2 and 3, are transmitted to the wires 19 and 20 connected to the rods (carrying the reeds) 15 and 16 via the reeds 13 and 14.

The quadruple crosspoint, according to the invention, operates in a same manner as the above described crosspoint of the FIG. 1. The electric circuitry of the quadruple crosspoint is shown in the FIG. 2.

The quadruple crosspoint having four pairs of contacts, as shown in the FIG. 2, has four two-wire inputs and a two-wire output. The input E1 is connected via the terminals 36 and 37 to the terminals 34 and 35 of the output S, when the contacts 01 and a2 are closed. Likewise, the input E2 is connected via the terminals 38 and 39 to the terminals 34 and 35 of S, when the contacts bl and b2 are closed. E3 and E4 are connected to S in similar manner.

FIG. 3 shows a quadruple two-contact crosspoint according to the invention wherein the glass capsule base is the only part of the glass capsule shown and wherein only one quadruple contact is shown for making the drawing clearer and easier to understand.

The assembly of contacts of the quadruple twocontact crosspoint are protected by a glass capsule, not particularly shown, which may be filled with an inert gas. Such a capsule is formed of two parts, a base 44 and a bell-shaped part, not shown, which is welded or scaled to the base 44 once the contacts have been mounted. The glass capsule is penetrated by four pairs of cores 4511 and 45b, 46a and 46b, 47a and 47b and 48a and 48b, and by two rods 49a and 49b. Cores and rods are preferably normal to the plane of the capsule base 44, they are sealed within it, for example, by means of glass beads. In a preferred embodiment, each pair of cores is obtained by sawing an U-shaped core. That U-shaped core is sealed in the glass capsule base 44 by its two vertical elements so that the horizontal part of the U-shaped core is parallel to the capsule base plane and that the distance from the base to the horizontal part is the same as for the other three U-shaped cores.

The traces determined by the U-shaped core vertical elements are in the plane defined by the base 44 equidistant from a central point. That central point is, for example, the center of the capsule base.- The U-shaped core planes cross the base plane along the sides of a square whose center is the base center point. The L- shaped cores such as 450 and 45b are obtained by sawing the horizontal middle part of the U-shaped element sealed, as above described, to the base. In a preferred embodiment, the U-shaped cores are previously made by electrically welding to U-shaped non-remanent magnetic material core two remanent magnetic material cores designed for extending the two vertical legs of the U so as to make possible welding glass with those elements; remanent magnetic materials are difficult to weld to glass in the present state of the art.

As is known in the art, it is recalled that qualities of a weld made electrically by melting materials forming the welded pieces are far better than those of pieces soldered with tin, as well concerning conduction as concerning strength.

The rods 49a and 49b made of conductive material are located at the same distance from the above mentioned center. Each rod carries a cross-shaped piece secured to its end inside the capsule. The rod 490 is secured to a cross-shaped piece 50a and the rod 49b is secured to a cross-shaped piece 50b (not shown). Each cross-shaped piece has four reeds above four cores respectively. The reeds 51a, 52a 53a 54a of the piece 500 welded to the rod 49a by electric welding, are respectively facing from above the contact areas of the cores 45a, 46a, 47a, 48a, forming the prop plane.

In a same manner, the reeds, of the not shown piece 50b, electrically welded to the rod 49b, are also located above and facing the contact areas of the cores 45b, 46b, 47b, 48b in a plane parallel to the prop plane.

The reeds are formed by a flexible conductor nonremanent material. The distance from a reed to the core contact area, such as the distance from the reed 51a to the contact area of the core 45a, is equal to a predeterminably-defined contact airgap, which is selected so that the reed may contact the core contact area under the action of the remanent magnetic field of the core magnetized as it will be explained in the following.

The four reeds of the cross-shaped piece are in the same plane parallel to the base plane. In a preferred embodiment according to the invention, the two planes, one defined by the reeds of the cross-shaped piece 50a and the other one defined by the reeds of the cross-shaped piece 50b, form only a single plane parallel to the prop plane, at a distance therefrom equal to the contact magnetic gap. Each piece will be made of two L-shaped pieces, each carrying two reeds along the L arms, and a mechanical link. The link of the piece 50a, such as 55a, has a shape so that it has no contact with the link of the piece 55b, not shown.

When the cores and the rods carrying the crossshaped pieces are placed and fixed, the capsule bell is welded to the base in a known manner. In a preferred embodiment, the glass capsule bell may have at its top an outlet permitting to adjust the contacts after the capsule manufacture, that outlet being then closed in an usual manner.

The cores 45a, 45b, 46a, 46b, 47a, 47b, 48a, 48b and the rods 49a and 49b pass through the base 44 of the glass capsule, the as it has previously been mentioned, and they are plugged in a printed circuit board 51. That board 51 has wires printed on its face which is not in contact with the base 44 of the glass capsule. Such wires are arranged so that each of them provides a connection either with a core or with a rod, which is soldered to it after having been passed through the printed circuit board 51. The part of each core outgoing from the board 51 is surrounded by either two coils or a coil with two windings as shown in the FIG. 3 in 56a, 57a, 57b, 58a, 58b, 59a, 59b on the cores 45a, 46a, 46b, 47a, 47b, 48a and 48b.

The connections of those coils are guided to and soldered to wires of the printed circuit board 51, which are designed for that purpose.

The ends of the cores 45a, 45b, 46a, 46b, 47a, 47b, 48a and 48b, which project out of the said coils are passed through holes pierced in the pole piece 61, such as the hole 60 for the end of the core 47b. The hole diameter is larger than the core diameter so as to avoid any core-polepiece contact, the said pole piece being a magnetic shield.

In operation, controls of pairs of cores such as 48a and 48b are provided according to the process described in conjunction with the crosspoint of the FIG. 1 so as to simultaneously provide contact of the two reeds with the cores which control them, for example the simultaneous contact of the reeds 51a and 51b with the cores 45a and 45b. FIG. 4 permits one to easily understand that operation since there is shown therein from the top the quadruple two-contact crosspoint de' scribed in relation to FIG. 3, with the two quadruple contacts in position.

In a preferred embodiment, the quadruple twocontact crosspoint according to the invention, such as shown in the FIGS. 3 and 4, has a height of about 25 mm and a lower cross-section surface of 500 mm.

In addition, the crosspoint according to the invention permits a replacement of four crosspoints usually used in matrices by a single quadruple crosspoint of small size; the size of the matrices may be considerably reduced while reliability thereof is increased.

While the principles of the present invention have been described herein in relation to specific embodiments, it is to be clearly understood that this description is only made by way of example and not as a limitation on the scope of the invention.

We claim:

1. A crosspoint comprising at least one pair of contacts with magnetic latching, each contact including a rigid inverted L-shaped electrically conductive core with at least a portion thereof constituting a remanent magnetic area and a flexible reed element made of electrically conductive, non-remanent magnetic material disposed proximate the top portion of said inverted L-shaped core, the two L-shaped cores of said at least one pair of contacts being arranged together in substantially an inverted U formation, the legs of which formation pass untouching through a pole piece arranged so as to form with said cores substantially an inverted U formation, and further comprising a coil arrangement disposed about each core on the part thereof constituting the leg portions of said inverted U formation, the arrangement of said coils and said cores being such as to provide that magnetic fluxes created in each core by its associated coil arrangement cause one of two conditions to occur in said at least one pair of contacts: (1) that said contacts achieve a rest condition as a result of the magnetic fluxes closing through a series path constituting the pair of cores and the pole piece; (2) that said contacts achieve a work condition wherein the reeds are attracted to and contacting the respective cores as a result of the magnetic fluxes closing through said cores and the respective flexible reeds, constituting a parallel flux condition.

2. The crosspoint according to claim 1 wherein said contacts are sealed in an insulator capsule with the reeds and the cores having connections penetrating through a wall of said capsule.

3. In a crosspoint arrangement with magnetic latching, the combination comprising 2m contacts arranged in an insulator capsule and divided into m pairs of contacts, m being an integer greater than zero, wherein each contact includes a rigid core element made of electric electrically conductive material and having at least a portion thereof composed of a remanent magnetic material, and a flexible reed element made of electrically conductive non-remanent magnetic material arranged to be movable for contacting the associated core, wherein each of said m contact pairs provides for one of its reeds to be arranged with one of the reeds of each of the other contact pairs in a first integral structure and the other of its reeds to be arranged with the other of the reeds of each of the other contact pairs in a second integral structure, and further comprising a rod-like rigid carrier element made of electrically conductive material associated with each of said first and second integral structures of reeds, said rods and'said 2m cores being sealed in the base of the capsule so as to form projections outside the capsule.

4. The crosspoint according to claim 3 further comprising 2m control coils mounted on the 2m cores in one-to-one correspondence, each coil comprising a pair of windings surrounding the core part located outside of the capsule, the crosspoint arrangement providing for connections to be made by means of conductive paths printed on a printed circuit board, with said board having apertures therein through which said cores and said rod-like elements pass, said board being arranged between the capsule and the control coils, with the board conductive paths being printed on the board side facing away from the capsule and each printed conductor being individually connected to one of the cores, rods or coil terminals in accordance with a predetermined configuration, and further comprising a magnetic shield including a pole piece of nonremanent magnetic material, having apertures therein for the ends of at least the cores to pass therethrough without contact between the shield and the cores.

5. The crosspoint according to claim 4 wherein each core has a contact area for enabling the associated reed to make contact therewith and forms a contact with the associated reed, wherein the 2m cores form 2m contact areas arranged in a single plane, called the prop plane.

6. The crosspoint according to claim 5 wherein the 2m reeds which contact the 2m cores are, in the rest position, in a plane parallel to the prop plane, with the distance from the reed face plane to'the prop plane being equal to the contact magnetic gap.

7. The crosspoint according to claim 6 wherein the configuration of the coils, each composed of two windings, and of the control pulses are designed for a coor dinate control of the crosspoint mounted in a matrix, the two contacts of a pair of contacts being in the same condition at a time, at rest when the remanent magnetizations of their respective cores are in series, and at work when the remament magnetizations of their respective cores are in parallel.

8. The crosspoint according to claim 7 wherein the individual ones of each pair of cores are substantially L-shaped andcurved one towards the other in substantially a U configuration inside the glass capsule, with the ends of the cores so arranged being on the same line for reducing the length of the lines of force therebetween when their magnetizations are in series.

9. The crosspoint according to claim 8 wherein the m reeds arranged with a rod are arranged in pairs located in opposite sectors of the plane which said reed arrangement defines parallel to the prop plane, the arrangement of said reeds and said rods being such that the pair of reeds which form along with the associated pair of cores a pair of contacts have one such reed connected to one rod and the other reed connected to the other rod.

10. The crosspoint according to claim 9 wherein each core comprises'two ends, one being free and carrying the contact area parallel to the prop plane and the other one being normal to the prop plane and sealed in the glass capsule base. I I 7 11. The crosspoint according to claim 10 wherein each reed has its longitudinal axis nonnal to the plane defined by its corresponding core, with each reed having the same relative position with respect to the corresponding core.

12. The crosspoint according to claim 11 wherein the m reeds carried by a'rod are made of a material different from the rod material, with said reeds being electrically welded to the rod so as to form a single piece.

t 3 I i 

1. A crosspoint comprising at least one pair of contacts with magnetic latching, each contact including a rigid inverted Lshaped electrically conductive core with at least a portion thereof constituting a remanent magnetic area and a flexible reed element made of electrically conductive, non-remanent magnetic material disposed proximate the top portion of said inverted Lshaped core, the two L-shaped cores of said at least one pair of contacts being arranged together in substantially an inverted U formation, the legs of which formation pass untouching through a pole piece arranged so as to form with said cores substantially an inverted U formation, and further comprising a coil arrangement disposed about each core on the part thereof constituting the leg portions of said inverted U formation, the arrangement of said coils and said cores being such as to provide that magnetic fluxes created in each core by its associated coil arrangement cause one of two conditions to occur in said at least one pair of contacts: (1) that said contacts achieve a rest condition as a resuLt of the magnetic fluxes closing through a series path constituting the pair of cores and the pole piece; (2) that said contacts achieve a work condition wherein the reeds are attracted to and contacting the respective cores as a result of the magnetic fluxes closing through said cores and the respective flexible reeds, constituting a parallel flux condition.
 2. The crosspoint according to claim 1 wherein said contacts are sealed in an insulator capsule with the reeds and the cores having connections penetrating through a wall of said capsule.
 3. In a crosspoint arrangement with magnetic latching, the combination comprising 2m contacts arranged in an insulator capsule and divided into m pairs of contacts, m being an integer greater than zero, wherein each contact includes a rigid core element made of electric electrically conductive material and having at least a portion thereof composed of a remanent magnetic material, and a flexible reed element made of electrically conductive non-remanent magnetic material arranged to be movable for contacting the associated core, wherein each of said m contact pairs provides for one of its reeds to be arranged with one of the reeds of each of the other contact pairs in a first integral structure and the other of its reeds to be arranged with the other of the reeds of each of the other contact pairs in a second integral structure, and further comprising a rod-like rigid carrier element made of electrically conductive material associated with each of said first and second integral structures of reeds, said rods and said 2m cores being sealed in the base of the capsule so as to form projections outside the capsule.
 4. The crosspoint according to claim 3 further comprising 2m control coils mounted on the 2m cores in one-to-one correspondence, each coil comprising a pair of windings surrounding the core part located outside of the capsule, the crosspoint arrangement providing for connections to be made by means of conductive paths printed on a printed circuit board, with said board having apertures therein through which said cores and said rod-like elements pass, said board being arranged between the capsule and the control coils, with the board conductive paths being printed on the board side facing away from the capsule and each printed conductor being individually connected to one of the cores, rods or coil terminals in accordance with a predetermined configuration, and further comprising a magnetic shield including a pole piece of non-remanent magnetic material, having apertures therein for the ends of at least the cores to pass therethrough without contact between the shield and the cores.
 5. The crosspoint according to claim 4 wherein each core has a contact area for enabling the associated reed to make contact therewith and forms a contact with the associated reed, wherein the 2m cores form 2m contact areas arranged in a single plane, called the prop plane.
 6. The crosspoint according to claim 5 wherein the 2m reeds which contact the 2m cores are, in the rest position, in a plane parallel to the prop plane, with the distance from the reed face plane to the prop plane being equal to the contact magnetic gap.
 7. The crosspoint according to claim 6 wherein the configuration of the coils, each composed of two windings, and of the control pulses are designed for a coordinate control of the crosspoint mounted in a matrix, the two contacts of a pair of contacts being in the same condition at a time, at rest when the remanent magnetizations of their respective cores are in series, and at work when the remament magnetizations of their respective cores are in parallel.
 8. The crosspoint according to claim 7 wherein the individual ones of each pair of cores are substantially L-shaped and curved one towards the other in substantially a U configuration inside the glass capsule, with the ends of the cores so arranged being on the same line for reducIng the length of the lines of force therebetween when their magnetizations are in series.
 9. The crosspoint according to claim 8 wherein the m reeds arranged with a rod are arranged in pairs located in opposite sectors of the plane which said reed arrangement defines parallel to the prop plane, the arrangement of said reeds and said rods being such that the pair of reeds which form along with the associated pair of cores a pair of contacts have one such reed connected to one rod and the other reed connected to the other rod.
 10. The crosspoint according to claim 9 wherein each core comprises two ends, one being free and carrying the contact area parallel to the prop plane and the other one being normal to the prop plane and sealed in the glass capsule base.
 11. The crosspoint according to claim 10 wherein each reed has its longitudinal axis normal to the plane defined by its corresponding core, with each reed having the same relative position with respect to the corresponding core.
 12. The crosspoint according to claim 11 wherein the m reeds carried by a rod are made of a material different from the rod material, with said reeds being electrically welded to the rod so as to form a single piece. 